Star Micronics TSP400 technical manual Detectors, Theory Of Operation

THEORY OF OPERATION

3-3. Detectors

(1)Paper-Out Detector

The paper-out detector is located at the paper entry slit. The detector consists of a reflective photosensor. The photosensor’s phototransistor remains ON while paper is present. It goes OFF when paper runs out, generating output of a paper-out signal.

(2)Black-Mark Detector

This detector senses black marks indicating print start positions. The detector is useful only with specially marked paper. Like the paper-out detector, the black-mark detector consists of a reflective photosensor. The photosensor’s phototransistor goes OFF when a black mark appears.

R

GND

+5V

Detection signal

R

R

Paper GND

+5V

Detection signal

R

Paper

Black mark

(Reflective photosensor) (Reflective photosensor)

Fig. 2-15 Paper-Out Detector Fig. 2-16 Black-Mark Detector

(3)Label Detector

The transmissive detector is used to detect print-start positions for labels. It operates by detecting the difference in light transmission between backing-only and backing-plus-label portions of the paper.

LightLight

Label paper

Quantity of	Backing paper
	Quantity of
transmitted light
	transmitted light

Fig. 2-17

5V

Paper

Detection signal

GND

Fig. 2-18 Label Detector

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